The genus Staphylococcus includes currently 32 described species and 15 subspecies. From the human clinical point of view, S. aureus is the most important, but some coagulase-negative species are emerging pathogens especially in nosocomial infections among critical care patients.
Certain species of the Staphylococcus genus are more frequently isolated as etiologic agents of a variety of infections in humans. The agents of most concern are S. aureus, S. epidermidis, S. haemolyticus, S. lugdunensis, S. warneri and S. saprophyticus. 
S. schleiferi has been considered a significant pathogen in some European countries but has only seldom been reported in the US, which demonstrates the variability of the local epidemiology of pathogens.
In veterinary medicine S. aureus, S. intermedius and S. hyicus are the most prominent pathogens
Staphylococcus aureus is one of the most common nosocomial pathogens. It is responsible for several diseases, ranging from superficial cutaneous abscesses to life-threatening intravascular infections. Its propensity to establish prolonged carriage among hospitalized patients and increasing resistance to antibiotics makes control of this organism within the hospital very difficult.
Knowledge of the epidemiology of S. aureus colonization among patients has shed new light on the potential difficulties in interrupting nosocomial transmission. Effective control of S. aureus within the hospital and community requires more aggressive measures that include earlier diagnosis of colonized patients, in other words, that include a step of screening.
Because Staphylococcus bacteraemia still increases in frequency, it is necessary and urgent to provide more rapid methods of detection and/or identification, using probes and/or primers more sensitive and more specific.